Climate

Beargrass, a perennial plant common in the northern Rockies, clings to the hillslopes near Logan Pass in Glacier National Park. Native Americans wove watertight baskets from the durable grass and made poultices and medicinal pastes from the tuberous roots. As land temperatures rise, alpine plants seek cooler and wetter habitat higher up hillsides. Eventually, they will run out of mountain.

Fall snowline advances down the southern peaks of the Livingston Range over the Middle Fork of the Flathead River. Alpine snowpack accumulates each winter, storing water that is slowly released during the warmer, drier months of the year. Snowmelt from the mountains accounts for roughly 80 percent of the west’s water supplies. Years with less snowfall tend to see more frequent and harsher severity fires in the late fall as the mountain reservoirs dry up.

Alpenglow illuminates the Livingston Range on the western edge of Waterton-Glacier International Peace Park. Trees, still standing after a wildland fire passed through the area, blanket the foothills. In recent years, the frequency, intensity and size of wildland blazes have increased along with the overall length of fire season. Scientists and managers attribute these increases to a variety of factors, including a changing climate, insect infestations and population booms, and drought.

On the eastern side of the divide, the Rocky Mountain Front is characterized by faulting, folding and overthrusting. The snowcapped mountains act as a seasonal water tower for the sagebrush prairies, making this transitional area ideal for ranching and farming. Energy exploration threaten the delicate balance of domestic stock and wildlife, already jeopardized by rising temperatures and periods of drought.

This glacial erratic just outside the Crown region in Yellowstone National Park is a monument to landscapes past. The boulder was likely deposited 20,000 years ago as the Cordilleran Ice Sheet retreated during the last period of glaciation. Estimates vary, but the glaciers that make Glacier National Park so distinctive could melt in as little as 30 years due to rapidly rising land temperatures. Displaced boulders and scooped valleys will be all that remain.